Electron discharge device and cooling accessories therefor



June 29,1937. o. w. 1KB 2,085,601

ELECTRON DISCHARGE DEVICE AND COOLING ACCESSORIES THEREFOR Filed Dec. 1, 1933 OOOOOO 'Inventoh:

OtEEZINka Bis towngg Patented June 29, 1937 ELECTRON DISCHARGE DEVICE AND COOL- IN G ACCESSORIES THEREFOR Otis W. Pike, Schenectady, N. Y., assignor to General Electric Company,,a corporation of New York Application December 1, 1933, SerialNo. 700,483

17 Claims. (01. 25027.5)

The present invention relates to electric discharge apparatus, and more particularly to devices. which carry large currents by means of ionized gas or vapor.

5 In accordance with my invention, I have devised an apparatus or accessory for these tubes which not only provides the necessary cooling of the anode, thereby allowing greater power output butalso offers a practical scheme for obtaining the proper temperature differential between selected parts of the envelope, thereby limiting and determining the position in the envelope at which the mercury condenses. The improvement also provides a simple arrangement for controlling the temperature of the condensing mercury.

Objects of the invention are to provide a liquid operated accessory for arc ,o'r glow discharge tubes containing ionizable, condensible mate- ,20 rial, which will positively determine and limit the position within the envelope at which the ionizable material condenses; to provide an accessory of this type for maintaining a tempera ture differential between that part of the envelope in which the ionizable material condenses and another envelope portion in which the material vaporizes, said temperature differential to be maintained regardless of changes in ambient temperature or load conditions; and to provide an accessory of this general character as will also serve to cool the anode as well as permit a ready control of the temperature of the condensed ionizable material.

The figure shows an elevational View of a typical tube provided with improved fluid cooling accessories which are shown in cross-section.

In the drawing, numeral l designates a bulbous envelope of an electrostatically controlled arc or glow discharge device which terminates at the lower end, as shown, in, a metal sleeve portion '2 sealed to the glass and at the upper end, as shown, in two glass reentrant stem members 3, 4. The metal sleeve 2 is provided at its lower end with a metal bushing 5, and at a position intermediate its length within its interior, there is a transversely extending metal plate (not shown) which supports a large metal rod 6 of relatively large diameter which carries the cathode structure I. A heat shield 8 may be secured to the metal rod 6.

The cathode structure includes a heater (not shown) a cathode casing (not shown), and one or more perforated heat shields. A cathode of thissort is adapted to provide a large supply of electrons for carrying heavy currents of an are or glow character. Electrical connection may be made to the cathode through the metal sleeve 2 and a lead 9 taken from the heater through, but insulated from the metal bushing 5. At the other end of the tube, there is an anode l0. This anode may conveniently constitute a hollow cylinder closed at the lower end but open at the end where it is sealed to the glass stem 3. An electrostatic control or grid member ll made of perforated sheet metal may be provided to control the are. This member conveniently is supported from the outer reentrant stem 4 to which it is secured by a ring clamp I2 and a connection l3 taken from the clamp through a transversely extending protuberance on the envelope to the exterior.

In addition to the electrodes, the envelope may contain an ionizable medium of the condensible type, for example, mercury.

When a tube of the type described is connected in appropriate and well-known circuits, a discharge having a substantially flat volt-ampere characteristic, passes between the cathode and anode, the starting of which is readily controllable by small charges on the grid electrode II. A

tube of this character is employed for the transla- 1 tion of extremely large currents and the are or glow discharge may cause an excessive amount ofheat to develop at the anode. In order to conduct this heat away rapidly, thereby obtaining greater output from the tube, it is desirable to cool the anode interior by a fluid, preferably water or oil. For this purpose, a pair of conduits 14 may be provided which communicate with the interior of the anode and through which a cooling fluid may be forced under pressure.

During operation of the tube, the mercury or other ionizable medium is in a partially vaporized and partially condensed state, the proportion of mercury in each state determining the vapor pressure within the tube which in turn, determines in part, at least, the rate of ionization and the facility with which the tube passes current. In order that the tube may operate properly, the vapor pressure must remain at'a constant predetermined value for a given current output regardless of changes in ambient temperature. It is also necessary that the mercury shall not be allowed to condense in the region of the anode, because the smallest amount of mercury which becomes deposited onthe anode may cause arcback if alternating current is employed for energization purposes. The mercury preferably shouldbe caused to condense at a position near the bottom of the tube, at the cathode end in case the tube is operated in a vertical position. In order to limit the positionat which the mercury condenses and to provide a position as remote from the anode as possible, it is apparent that the portion of the envelope at which it is desired to condense the mercury should be maintained cooler than all the remaining portions of the tube. In other words, there must be provided a temperature differential between the coolest or condensing portion of the tube and all other portions, which differential must be maintained under all conditions of operation, even when the average temperature of the tube is changed.

In accordance with my invention, there is provided an accessory of simple construction which not only maintains the necessary temperature differential under all conditions of operation and ambient temperatures, but in addition provides abundant cooling for the interior of the anode as well as for the arc itself. This accessory may take the form of a reservoir or compartment I5 which surrounds the end of the tube where it is desired to condense the'mercury vapor, for example, the lower or cathode end, and for this reason is maintained at the coolest temperature, also a' larger compartment I6 which may surround the remaining parts of the envelope which contain the anode and other electrodes. In the figure, the compartment I6 is shown, in an exemplary manner as surrounding the bulbous part of the envelope and is located in such a position [as to abstract a considerable'quantity of'heat radiated by'the arc or glow. These compartments are jointed together by a pipe or conduit H, and to the compartment l6, there may also .be joined a conduit I 8 which communicates with one of the vertical pipes M. The arrangement is such that a cooling fluid such as oil or water may be passed first, through the compartment l5, as indicated by the arrows, then through the compartment 16 and finally through the. interior of the anode I0.

'It is apparent that during the operation of the tube, the fluid is introduced into the compartment in a cool state and it becomes somewhat heated- It is then forced into compartment 16 where it abstracts heat from the arc and finally flows into the'interior of theanode where it is still sufficiently cool to lower the temperature of this electrode. The water in flowing through the reservoir and conduit system automatically serves to maintain the lower portion of the tube at a cooler temperature than the upper portion because the heat produced in the arc or glow discharge itself is absorbed to a great extent by the .Water in the compartment l6. The compartment 15 ispositioned so remote from the heat radiating elements of the tube that the fluid contained therein does not become greatly heated. It is clear that the. temperature difierential between the fluids in the two compartments producesa temperature differential between the two portions of the'envelope which they surround and this temperature differential is maintained even when the average temperature of the entire tube is changed due to an increase or decrease in the amount of current flowing between the electrodes or'due to changes in ambient temperature.

I Bymaintaining the lower or cathode end of the vice, but in addition'provides the necessary temperature differential between the condensing and vaporizing portions of the envelope and limits the position of the condensing material to a region where it can produce no deleterious eifects such as arc-back. It is also evident that the temperature of the coolest or condensing portion of the envelope may be effectively controlled by simply regulating the velocity or temperature, or both, of the cooling fluid as it flows into the first compartment.

While I have shown the envelope as taking a bulbous form, it is apparent that the improved accessory may be advantageously used with other forms of envelope, with suitable changes in the shape of the compartments. In fact, the inner metal wall of the compartment 16 may constitute part of the envelope, in which case the bulbous glass portion would be discarded and the tube given a cylindrical shape of uniform diameter. Furthermore, the improved accessory may be satisfactorily applied to a tube of the large external anode type in which the anode itself constitutes the major part of the envelope and includes the cathode and other cooperating electrodes.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In combination, an electron discharge device comprising an envelope containing cooperating electrodes including a solid thermionic cathode, and a condensible ionizable medium, a compartment surrounding the envelope in the region of theelectrodes, and a compartment surrounding the envelope in the region of the said material when in a condensed state, said compartments each having an inlet and an outlet conduit and being sequentially connected to permit circulation of a temperature controlling fluid therethrough. 1

2. In combination, an electron discharge device comprising an envelope containing an anode, a solid thermionic cathode and a condensible ionizable material in the region of the cathode, a compartment surrounding the envelope in the region of the anode, and a compartment surrounding the envelope in the region of the cathode, said compartments each having an inlet and an outlet conduit and being sequentially connected to permit circulation of a temperature controlling fluid therethrough.

3. In combination, an electron discharge device comprising an envelope containing cooperating electrodes and a condensable ionizable material, a compartment surrounding the envelope in the region of the electrodes, and a compartment surrounding the envelope in the, region of the said material when in a condensed state, andv means for passing a temperature regulating fluid, first through the compartment which surrounds the envelope in the region of the said condensed material and then through the compartment which surrounds the envelope in the region of the electrodes, whereby the two portions of the envelope are maintained at diiferent temperatures.

4. In combination, an electron discharge device comprising an envelope containing cooperating electrodes and a condensible ionizable material, a portion of which vaporizes under operating conditions and another portion remains in a condensed state in another part of the envelope,

.meansincluding a compartment adapted to receive a fluid for maintaining. the part of the en- 'velope in which the said material condenses at' a lower temperature than thepart of the-envel ope in which the said material vaporizesfi 5. In combination, an electron discharge device comprising an envelope containing cooperating electrodes and a conclensible ionizable-material, said envelope being divided into two portions, in

one of which the said material condenses during comprising an envelope containing cooperating electrodes and [a condensible ionizable material,

a portion of which vaporizes under operating conditions and another portion remains in a condensed state in a different part of the envelope, means for. maintaining the envelope portion in which the ionizable material condenses at a cool or temperature than the envelope portion in which the ionizable material vaporizes, said means including a pair of compartments containing temperature-regulating fluid, one of said compartments surrounding the vaporizing part of the envelope and the other compartment surrounding the condensing part of the envelope, the fluid in the compartment which surrounds the vaporizing part of the envelope being at a higher average temperature than the fluid in the compartment which surrounds the condensing part of the envelope.

'7. In combination, an electron discharge device comprising an envelope containingv a hollow anode adapted to be fluid-cooled, a cathode and a condensible ionizable material, a plurality of fluid jackets, one'o-f said jackets surrounding the envelope in the region of the electrodes, another of said jackets surrounding the envelope in the region where the ionizable material condenses during operation, said jackets being in communication with one another and with the interior of said anode whereby a temperature differential may be established and maintained between the envelope portions and the anode may be fluidcooled.

8. In combination, an electron discharge device comprising an envelope containing a cathode, an anode and an ionizable material which condenses and vaporizes during operation, said cathode being mounted at one end of the envelope and said anode being mounted at the opposite end of the envelope, at fluid jacket surrounding the envelope at the cathode end and a fluid jacket surrounding the envelope in the region of the space between the cathode and anode, said jackets being in communication with one another.

9. In combination, an electron discharge device comprising an envelope provided with two tween one of the and vaporizes during operation, a fluid jacket surroundingitheenvelope in the region of the anode, a. fluid'jacket surrounding the envelope in a regionremotefrom the anode at a position where the ionizable material condensesjand a cenduitextending between :saidi jackets and bejackets and the interior of the anode. 7 I

11. In combination, an electron discharge device"comprising an envelope provided with two end cylindrical portionsaand an intermediate bulbous portion, a solid thermionic cathode structure mounted inone of the endlportions and a hollow anode mounted in the other end portion,

a fluid jacket surrounding the bulbous portion and a fluid jacket surrounding the cathode end portion, said jackets being in communication with one another and with theinteriorof said anode.

12. In combinationyan electron discharge device comprising an envelope containing a ther mionic cathode and a material adapted to be vaporized and ionized in order to support an arclike discharge at the impressed voltages, a portion of said envelope being adapted to operate at a temperature sufficiently high to maintain the ionizable material in a. vaporous condition, and

another portion of the envelope being adapted to operate at a temperature sufficiently low to cause condensation of a portion of the vapor, and means for presenting a cool fluid to the portion of the envelope wherein the ionizable material is condensed, and means for presenting a fluid at a higher temperature than the said cool fluid to the portion of the envelope wherein the ionizable material is vaporized, whereby a temperature differential is established and maintained between the said two envelope portions under all ambient temperature and operating conditions.

13. An electric discharge device comprising an envelope containing a thermionic cathode and a material adapted to be vaporized and ionized in order to support an arc-like discharge, a portion of said envelope being adapted to operate at a temperature suificientlly high to maintain the ionizable material in a vaporous condition, and another portion of the envelope being adapted to operate at a temperature sufliciently low to cause condensation of a portion of the vapor, and means comprising a water jacket for presenting a cool fluid in heat-absorbing relation to the portion of the envelope wherein the ionizable material is condensed, and means including a water jacket for presenting a fluid at a higher temperature than the said cool fluid in heat-absorbing relation to the portion of the envelope wherein the ionizable material is in a vaporous condition, whereby a temperature differential is established and maintained between the two envelope portions under all ambient temperature and operating conditions.

14. In combination, an electrical discharge device comprising an envelope containing a plurality of electrodes, including a solid thermionic cathode, and a condensible, ionizable material positioned remote therefrom, a compartment surrounding the envelope in the region of said electrodes, and a compartment surrounding the envelope in the region of the condensed material, said compartments each having an inlet and an outlet conduit and. being sequentially connected to permit circulation of a temperature-controlling fluid therethrough.

15. In combination, an electron discharge device including a plurality of electrodes and a con- -anode andan ionizable material which condenses 7 vice including an anode and a condensible, ionizable material, a condensing surface for said material, and means for maintaining said surface at a lower temperature than said anode, said means including a plurality of compartments each havingan inlet and an outlet conduit and being sequentially connected to permit circulation of a temperature-controlling fluid therethrough, said compartments being respectively positioned in heat-transferring relation to said surface and to said anode.

.17. In combination, an electron discharge device comprising an envelope containing a plurality,'

'of electrodes and a condensible, ionizable material, a portion of said envelope serving as a condensing surface for said material, and means for maintaining saidenvelope portion at a lower temperature than all other portions of the envelope and also at a lower temperature than said electrodes, said means including a plurality of compartments each having an inlet and an outlet conduit and being sequentially connected to permit circulation of a temperature-controlling fluid therethrough, said compartments being in heattransferring relation respectively to said portion of said envelope and to said electrodes.

OTIS W. PIKE. 

